Amine-Functionalized Carbon Bowl-Supported Pd-La(OH)3 for Formic Acid Dehydrogenation

Formic acid (HCOOH, FA) is emerging as an appealing carrier for hydrogen storage owing to its renewability, a high volumetric capacity of 53 g H2/L, and convenient storage/transportation as a liquid. It is highly desired but still a challenge to search highly efficient catalysts to realize hydrogen evolution from FA. Here, monodispersed and ultrasmall Pd-La(OH)3 nanoparticles (NPs) anchored on amine-functionalized N-doped porous carbon bowl (N-PCB-NH2) substrates have been fabricated through a facile wet chemistry approach. As a result of the ultrafine size of Pd-La(OH)3 NPs (1.6 nm), the deprotonation ability of La(OH)3 and amine groups, and the strong metal-support interaction between Pd-La(OH)3 and N-PCB-NH2, the as-prepared Pd-La(OH)3/N-PCB-NH2 catalyst exhibits 100% H2 selectivity and exceptional catalytic property with a high turnover frequency value up to 9585 h-1 for FA dehydrogenation at 323 K, which is superior to most of the heterogeneous catalysts ever reported. Kinetic isotope effect measurements demonstrate that the C-H bond cleavage is a rate-determining step in the FA dehydrogenation reaction as compared to the O-H bond dissociation. This work presents a feasible approach to synthesize supported ultrafine metal NP catalysts with porous bowl structures for H2 generation from FA.